CN110945605B - Method for manufacturing laminated electronic component - Google Patents

Abstract

A sintered body in which ceramic layers and internal electrodes were alternately laminated was obtained. A1 st external electrode connected to the internal electrode is formed on a side surface of the sintered body. The sintered body having the 1 st external electrode formed thereon was entirely coated with glass. The 2 nd external electrode was formed on the side surface of the glass-coated sintered body. With this method, in the laminated electronic component, the electrical connection between the internal electrode and the external electrode can be stabilized.

Description

Method for manufacturing laminated electronic components

technical field

The present invention relates to a method of manufacturing laminated electronic components used in various electronic devices.

Background technique

In recent years, electronic components for surface mounting include various types of electronic components in addition to multilayer ceramic capacitors and multilayer ceramic varistors. There is no particular problem when the size of these electronic parts is small, but if the size of the electronic parts becomes large due to handling large capacity or high current, etc., it may be caused by the difference in linear expansion coefficient between the circuit board material and ceramics. Mechanical stress is generated and electronic components are damaged. Therefore, in a conventional electronic component, a lead terminal processed from a metal plate is attached to external electrodes on both end surfaces of the electronic component, and the lead terminal is mounted on a circuit board via the lead terminal.

For example, Patent Document 1 discloses a conventional electronic component similar to the above-mentioned electronic component.

prior art literature

patent documents

Patent Document 1: JP-A-2000-306764

Contents of the invention

A sintered body in which ceramic layers and internal electrodes were alternately laminated was obtained. A first external electrode connected to the internal electrode is formed on the side surface of the sintered body. Glass coating is performed on the entire sintered body on which the first external electrodes are formed. A second external electrode was formed on the side surface of the glass-coated sintered body. According to this method, the electrical connection between the internal electrodes and the external electrodes can be stabilized when the electronic component is laminated.

Description of drawings

FIG. 1A is a perspective view of a laminated electronic component in the embodiment.

FIG. 1B is a cross-sectional view at line 1B-1B of the laminated electronic component shown in FIG. 1A .

2 is a cross-sectional view illustrating a method of manufacturing a laminated electronic component in the embodiment.

3 is a cross-sectional view illustrating a method of manufacturing a laminated electronic component in the embodiment.

4 is a cross-sectional view illustrating a method of manufacturing a laminated electronic component in the embodiment.

5 is a cross-sectional view illustrating a method of manufacturing a laminated electronic component in the embodiment.

6 is a cross-sectional view showing a method of manufacturing a laminated electronic component in the embodiment.

7 is a cross-sectional view showing a method of manufacturing a laminated electronic component in the embodiment.

8 is a cross-sectional view illustrating a method of manufacturing a laminated electronic component in the embodiment.

detailed description

FIG. 1A is a perspective view of a laminated electronic component 1000 in the embodiment. FIG. 1B is a cross-sectional view at line 1B-1B of the laminated electronic component 1000 shown in FIG. 1A . In the embodiment, the multilayer electronic component 1000 is a multilayer ceramic varistor.

The laminated electronic component 1000 includes: a sintered body 11, an insulating layer 15 provided on the sintered body 11, external electrodes 13A and 13B provided on the sintered body 11, an external electrode 14A provided on the external electrode 13A, and an external electrode 14A provided on the external electrode 13A. External electrode 14B on external electrode 13B, plating layer 16A provided on external electrode 14A, plating layer 16B provided on external electrode 14B, bonding material 18A provided on plating layer 16A, The bonding material 18B provided on the plating layer 16B, the lead terminal 17A bonded to the plating layer 16A, that is, the external electrode 14A through the bonding material 18A, and the lead terminal 17A bonded to the plating layer 16B, that is, the external electrode 14B through the bonding material 18B 17B. Sintered body 11 includes a plurality of insulating layers 22 and internal electrodes 12A and 12B that are alternately stacked. The sintered body 11 has: a side surface 11A where the internal electrode 12A is exposed; a side surface 11B where the internal electrode 12B is exposed; a mounting surface 11C connected to the side surfaces 11A and 11B; an opposite surface 11D connected to the side surfaces 11A and 11B and opposite to the mounting surface 11C; Surface 11E connected to side surfaces 11A, 11B, mounting surface 11C, and facing surface 11D; surface 11F connected to side surfaces 11A, 11B, mounting surface 11C, and facing surface 11D and opposite to surface 11E. The insulating layer 15 is provided on the mounting surface 11C, the opposite surface 11D, and the surfaces 11E, 11F of the sintered body 11 . Multilayer electronic component 1000 is configured to be mounted on mounted object 2001 by connecting lead terminals 17A, 17B to mounted object 2001 such as a circuit board.

A method for manufacturing the laminated electronic component 1000 will be described below. 2 to 8 are cross-sectional views illustrating a method of manufacturing the laminated electronic component 1000 .

A mixed material obtained by adding bismuth oxide or the like to zinc oxide and mixing a plasticizer, a binder, and the like is formed into a sheet to form a plurality of green sheets 122 . A binder or the like is mixed with the silver powder to form the paste 112 for internal electrodes. After printing the internal electrode paste 112 on the plurality of green sheets 122 and stacking the green sheets 122 and the internal electrode paste 112 alternately, the plurality of laminated bodies 111 shown in FIG. 2 are formed by singulation. A plurality of sintered bodies 11 are obtained by firing a plurality of laminated bodies 111 at about 900°C. At this time, green sheet 122 is fired simultaneously with internal electrode paste 112 to form insulating layer 22 and internal electrodes 12A and 12B, respectively. The chamfering of the corners of the sintered bodies 11 is performed by mixing and stirring a plurality of sintered bodies 11 with abrasives, and the internal electrodes 12A, 12B are formed on the opposite sides of the sintered body 11 , respectively. 11B is exposed. Thereby, the sintered compact 11 shown in FIG. 2 can be obtained. The internal electrode 12A is not exposed on the side surface 11B, and the internal electrode 12B is not exposed on the side surface 11A. The size of the sintered body 11 is about 7 mm in width, about 9 mm in length, and about 3 mm in height.

A conductor paste obtained by mixing a binder or the like with silver powder is prepared. Next, a plurality of sintered bodies 11 are arranged so that the exposed side surfaces 11A of the internal electrodes 12A are aligned and the exposed side surfaces 11B of the internal electrodes 12B are aligned, and conductor paste is printed on the side surfaces 11A, 11B of the sintered bodies 11 so as to cover the exposed insides, respectively. The electrodes 12A and 12B are fired at about 800° C. to form the external electrodes 13A and 13B to obtain the intermediate member 1001 . At this time, since external electrodes 13A, 13B are formed in direct contact with internal electrodes 12A, 12B exposed from side surfaces 11A, 11B, electrical connection between internal electrodes 12A, 12B and external electrodes 13A, 13B can be stabilized. The thickness of the external electrodes 13A, 13B is about 20 μm. The region of insulating layer 22 sandwiched between internal electrodes 12A and 12B determines the electrical characteristics of laminated electronic component 1000 . Since the external electrodes 13A and 13B use a conductor paste in which silver powder is mixed with a binder, etc., it is possible to prevent extra substances that affect the electrical characteristics of the laminated electronic component 1000 from diffusing to the area, such as dielectrics other than the silver powder that are conductors, and to make the electrical Characteristic stabilization.

As shown in FIG. 4 , for example, a suspension of silica powder 502 composed of submicron-sized silica powder 502 and a medium solution 503 in which the silica powder 502 is dispersed is prepared, that is, a coating liquid 501 for glass coating. . Next, as shown in FIG. 4 , intermediate member 1001 , which is sintered body 11 on which external electrodes 13A, 13B were formed, is immersed in coating liquid 501 to perform glass coating on the entire intermediate member 1001 . At this time, silica powder 502 adheres to the surfaces of external electrodes 13A, 13B and surfaces 11C to 11F of sintered body 11 (see FIGS. 1A and 1B ). Thereafter, the intermediate member 1002 shown in FIG. 5 is formed by heat-treating the entirety of the glass-coated intermediate member 1001 at about 900°C. The silicon dioxide powder 502 attached to the surfaces 11C to 11F of the green body of zinc oxide of the sintered body 11 reacts with the zinc of the zinc oxide of the insulating layer 22 to form a stable insulating layer on the entire surfaces 11C to 11F of the sintered body 11 15. By forming such a stable insulating layer 15 on the entire surfaces 11C to 11F exposed from the external electrodes 13A and 13B other than the external electrodes 13A and 13B, a highly reliable laminated electronic component 1000 can be obtained. In intermediate member 1002 shown in FIG. 5 , silicon dioxide is attached to the surfaces of external electrodes 13A and 13B to form silicon dioxide layers 51A and 51B, respectively.

A mixed paste obtained by mixing a binder and the like with silver powder and glass frit is prepared. Next, a plurality of sintered bodies 11, that is, the intermediate member 1002 is arranged so that the sides on which the external electrodes 13A are formed are aligned and the sides on which the external electrodes 13B are formed are aligned, and a mixed paste is applied to the external electrodes 13A and 13B so that External electrodes 13A and 13B are completely covered so that 13A and 13B are not exposed, and fired at about 700° C. to form external electrodes 14A and 14B shown in FIG. 6 . External electrodes 14A, 14B have larger areas than external electrodes 13A, 13B, and surround external electrodes 13A, 13B, respectively. At this time, part of the silicon dioxide in the silicon dioxide layers 51A and 51B attached to the surfaces of the external electrodes 13A and 13B diffuses into the mixed paste, that is, the glass frit in the external electrodes 14A and 14B. Thereby, external electrodes 13A, 13B and external electrodes 14A, 14B are reliably electrically connected. As a method of applying the mixed paste, a printing process is preferably used, but a dipping process may also be used. However, even in this case, it is preferable to apply only to almost the sides of the intermediate member 1002 . Since the silver paste containing glass frit is used to form external electrodes 14A, 14B, external electrodes 14A, 14B can be fixed to external electrodes 13A, 13B and sintered body 11 with sufficient strength.

Next, by electroplating, plating layers 16A, 16B are respectively formed on the external electrodes 14A, 14B to form the individual member 1003 shown in FIG. 7 . The plating layer 16A ( 16B) has a two-layer structure including a nickel plating layer formed on the external electrode 14A ( 14B) and a tin plating layer formed on the nickel plating layer. In an embodiment, the thickness of the nickel plating layer is about 3 μm, and the thickness of the tin plating layer is about 5 μm.

Lead terminals 17A and 17B are prepared by punching an iron or phosphor bronze plate into a predetermined shape and bending it into an L-shape. Plated layers of nickel and tin are formed on the lead terminals 17A, 17B, and bonding layers 18A, 18B are respectively provided with a bonding material such as solder in areas that are in contact with the external electrodes 14A, 14B. Next, as shown in FIG. 8 , lead terminals 17A, 17B are connected to plating layers 16A, 16B, that is, external electrodes 14A, 14B, respectively. The lead terminals 17A, 17B are brought into contact with the external electrodes 14A, 14B and the bonding layers 18A, 18B, heated by laser or the like to melt the solder of the bonding layers 18A, 18B, and the lead terminals 17A, 17B are connected to the external electrodes 14A, 14B. Thereby, the laminated electronic component 1000 with a lead terminal can be obtained. External electrodes 13A, 13B and external electrodes 14A, 14B are formed by printing, so that the surfaces of external electrodes 14A, 14B (plating layers 16A, 16B) in contact with lead terminals 17A, 17B can be flattened, and bonding layer 18A can be formed. , 18B extend from the side surfaces 11A, 11B of the sintered body 11 beyond the mounting surface 11C along the lead terminals 17A, 17B to the mounting object 2001 . With such a configuration, the stress from the lead terminals 17A, 17B side can be dispersed, and the reliability of the multilayer electronic component 1000 can be further improved.

Individual component 1003 shown in FIGS. 7 and 8 has mounting surface 53C facing mounting object 2001 when laminated electronic component 1000 is mounted on mounting object 2001 (see FIG. 1B ) such as a circuit board, and mounting surface 53C. The opposite side is across from 53D. When the lead terminals 17A, 17B are connected to the external electrodes 14A, 14B, they are arranged so that the opposite surface 53D of the separate member 1003 is set downward and abuts against the reference surface 54, so that the ends 117A, 117B of the lead terminals 17A, 17B The lead terminals 17A, 17B are connected to the external electrodes 14A, 14B in a state of being in contact with the reference surface 54 and aligned with the opposing surface 53D. The external electrodes 14A, 14B formed by the method described above can hardly be attached to the opposite surface 53D of the individual member 1003 . Therefore, the mounting positions of the lead terminals 17A and 17B can be stabilized by the alignment described above, and the multilayer electronic component 1000 can be easily mounted on the mounted object 2001 with high precision, thereby improving mountability.

In the above-mentioned conventional electronic component, if a positional displacement occurs when the lead terminal is mounted, the following problems arise when it is mounted on a circuit board. The existing surface-mounted electronic components with lead terminals are mounted with lead terminals on the components used for surface mounting. In these electronic components, in order to be mounted on the circuit board, the mounting surface of the electronic components is dipped by dipping or the like. Form the electrodes. Therefore, electrodes are also formed on other surfaces of the electronic component, such as the upper surface and the side surface, in addition to the mounting surface. If the lead terminal is mounted based on the outer shape of the electronic component, a positional shift may occur due to a difference in thickness of the electrodes.

As described above, the multilayer electronic component 1000 in the embodiment can be easily mounted on the mounting object 2001 with high precision, and the mountability can be improved.

When positioning the lead terminals 17A and 17B, the part of the individual member 1003 that is farthest from the mounting surface 53C on the opposite side to the mounting surface 53C comes into contact with the reference surface 54 . In the individual component 1003 shown in FIG. 8 , the plating layers 16A, 16B are in contact with the reference plane 54 . In the embodiment, in order to reliably suppress the difference in the position of the lead terminals 17A, 17B caused by the difference in the sintered body 11, it is preferable that the insulating layer 15 is farther away from the mounting surface 53C than the external electrodes 14A, 14B. Surface 53C.

-Symbol Description-

11 Sintered body

12A, 12B Internal electrodes

13A, 13B External electrodes (1st external electrodes)

14A, 14B External electrode (2nd external electrode)

15 insulation

16A, 16B plating layer

17A, 17B wire terminals

18A, 18B bonding layer

Claims (9)

1. A method of manufacturing a laminated electronic component, comprising: A step of preparing a laminate having alternately stacked ceramic layers and internal electrodes and having a side surface where the internal electrodes are exposed; The step of firing the laminated body to obtain a sintered body having a side surface where the internal electrodes are exposed; a step of forming a first external electrode connected to the internal electrode on the side surface of the sintered body; A step of forming an insulating layer on the entire surface of the sintered body other than the first external electrode by glass-coating the entirety of the sintered body having the formed first external electrode; forming a second external electrode on the first external electrode to obtain a single component including the sintered body, the insulating layer, the first external electrode, and the second external electrode; and In the step of connecting the second external electrode to a plate-shaped lead terminal via a bonding layer, The individual component has a mounting surface facing the mounting object in a state where the laminated electronic component is mounted on the mounting object, In a state where the multilayer electronic component is mounted on an object, the bonding layer extends from the second external electrode along the lead terminal beyond the mounting surface. 2. The method of manufacturing a laminated electronic component according to claim 1, wherein: The step of forming the first external electrode includes the step of forming the first external electrode on the side surface of the sintered body by a printing process. 3. The method of manufacturing a laminated electronic component according to claim 2, wherein: The step of forming the second external electrode includes the step of forming the second external electrode on the first external electrode by a printing process. 4. The method of manufacturing a laminated electronic component according to claim 1, wherein: The step of forming the first external electrode includes the step of applying a conductor paste containing silver to the side surface of the sintered body, The step of forming the second external electrode includes the step of applying a mixed paste containing silver and glass frit to the first external electrode. 5. The method of manufacturing a laminated electronic component according to claim 4, wherein: The step of forming the second external electrode further includes the step of firing the mixed paste applied to the first external electrode. 6. The method of manufacturing a laminated electronic component according to claim 4, wherein: The step of forming the insulating layer includes immersing the sintered body having the formed first external electrode in a suspension of silica powder to coat the glass, thereby forming the insulating layer. layer such that silicon dioxide remains on the surface of the first external electrode, The step of forming the second external electrode includes the step of applying the mixed paste on the surface of the remaining silicon dioxide of the first external electrode. 7. The method of manufacturing a laminated electronic component according to claim 4, wherein: The step of forming the first external electrodes further includes the step of firing the applied conductive paste. 8. The method of manufacturing a laminated electronic component according to claim 1, wherein: It also includes the step of connecting a lead terminal to the second external electrode. 9. The method of manufacturing a laminated electronic component according to claim 8, wherein: The step of forming the second external electrode includes the step of obtaining a single member including the sintered body, the insulating layer, the first external electrode, and the second external electrode, The individual component has a mounting surface that faces the mounting object when the laminated electronic component is mounted on the mounting object, and a surface opposite to the mounting surface, The step of connecting the lead terminal to the second external electrode includes: the step of positioning said wire terminal by aligning said opposite face of said separate component with an end of said wire terminal; and A step of connecting the positioned lead terminal to the second external electrode.

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